Method for operating a multi-burner system by means of combustion air pressure measurement and regulation

ABSTRACT

The invention relates to a method for operating a multiple burner system ( 32 ), which comprises a number of burner groups, whereby each burner group have at least one air duct ( 3,8 ) assigned, via which air is supplied to a burner group, whereby each burner group has at least one k th  air channel ( 4,6 ) by which the supplied air splits up into a k th  air, whereby for each k th  air channel ( 4,6 ) of all burner groups an air pressure value for the k th  air is measured, whereby all measured air pressure values for the k th  air are compared with one another, whereby it is checked if air pressure values for the k th  air of the burner groups differ from one another, whereby deviating air pressure values of the k th  air inside the k th  air channels ( 4,6 ) are modified.

TECHNICAL FIELD

The invention relates to a method and a setup for the operation of amultiple burner system, which is part of a furnace.

BACKGROUND

A combustion chamber of a furnace can comprise of multiple burners,which feed air to the combustion chamber, which is burnt in the chamberin combination with a fuel. Each burner can thereby, due to its geometryand/or construction, be designed to have several air channels, with airsupplied via each channel. To ensure that the fuel is burnt efficientlyin the combustion chamber, the amount of air supplied must be dosedcorrectly.

In many furnaces, specifically in those found in oil refineries, it isnormally not possible to achieve an air distribution with uniform andappropriate fuel-to-air ratio for each burner or burner group. Thereason is that, due to cost constraints, there are almost always no airflow measurements for individual burners, except maybe for large steamboilers. If anything, only the total amount of combustion air to afurnace or respectively to all burners combined is measured.Furthermore, there are normally no automatically adjustable air supplymodules or automatic controls for the individual burners or burnergroups.

Spot measurements, e.g. with a pitot tube, are possible, but tootime-consuming and therefore not economical in practice, as the effortfor such measurements at furnaces with many burners, e.g. 70 at aminimum, is considerable.

Against this background, a method and setup with the attributes ofindependent patent claims are introduced. Details of the invention canbe derived from the dependent patent claims and this description.

SUMMARY

The invention relates to a method for the operation of a multiple burnersystem, comprising a number of burner groups, each consisting of atleast one burner. Air is supplied to each burner group throughout atleast one associated air duct. Each burner group has at least one k^(th)air channel, which splits the air, supplied from the air supply duct,into a k^(th) air and k^(th) fraction of air, respectively. With theproposed method, the air pressure of the k^(th) air and the k^(th)fraction of air, respectively, is measured for the k^(th) air channel ofeach burner group. All measured air pressure values for the k^(th) airof each burner group are then compared with one another, whereby it ischecked, whether the values for the k^(th) air of all burner groups aredeviating from one another. Deviating values of the measured airpressures of the k^(th) air in the k^(th) air channel of all burnergroups will be modified and potentially equalised and/or adjusted.

As part of the configuration of the method, all measured values of thek^(th) air are usually collected and compared in a central location.

Depending on the definition, the multiple burner system, to which themethod will be applied, comprises a number of burner groups, wherebyeach burner group consists of at least one burner. At least one burnerof each burner group is thereby associated with at least one air duct,which feeds air to at least one burner of the burner group. Each burneralso has a k^(th) air channel, which splits the air into a k^(th) air,whereby for each k^(th) air channel of all burners the air pressurevalue of the k^(th) air is measured, whereby all measured air pressurevalues of the k^(th) air of the burners are compared with one another,whereby it is checked, if the air pressure values of the k^(th) airdiffers from one another, whereby differing air pressure values of thek^(th) air inside the k^(th) air channel will be modified and equalized.

One or more air supply duct is allocated to at least one burner groupand/or burner. Each burner group and/or each burner comprises of atleast one air channel, namely the k^(th) air channel. Therefore e.g. foreach burner of a burner group, that is to say each m^(th) burner, atleast one air channel, that is to say the k^(th) air channel, splits offair, that is supplied from the air duct, namely into a k^(th) air andtherefore the air into at least a k^(th) fraction, whereby normally itsplits off in several fractions. Generally every burner group and/orevery burner comprises of an air supply duct connection, through whichthe k^(th) air channel is connected with the air duct. Due to thegeometry of the burner group and/or the burner respectively the airrouting inside the burner group casing and/or the burner casing, thesupplied air splits up throughout the k^(th) air channel into a k^(th)air respectively a k^(th) fraction.

It can be envisaged, that every burner splits up air, that is suppliedfrom the air duct, throughout a number of air channels into acorresponding number of air fractions, e.g. primary air as a first air,secondary air as second air and tertiary air as a third air andtherefore into a possible k^(th) air.

The method envisages that all air fractions, that are supplied to allburners, are controlled and therefore driven and/or regulated, whichalso includes, that all air pressure values of the k^(th) air arecompared with one another. Thereby only values for the air pressures fora k^(th) air respectively the k^(th) fraction of the supplied air,meaning primary, secondary or tertiary air are compared to one anotherand are if needed be adjusted. Like this the values for the k^(th) airrespectively the k^(th) fractions of the supplied air are compared withone another and if needed to be adjusted. Like this the values for themultiple burner system are equalized for each air fraction and thereforeeach k^(th) air. After this kind of adjustments respectively balancingthe values for various air fractions can still be deviating to oneanother.

With the help of gathering all measured values for the air pressures atone central location and with the proposed pressure measuring setup, thek^(th) air of each burner or burner group can be registered andmonitored as well as modified with the help of the air modules, wherebya favorable fuel-to-air ratio on all burners or burner groups can beachieved.

Due to the construction of a burner group and/or a burner it is possibleto separate the air into fractions, without a need for several airducts. With the method normally only those fractions of the k^(th) airin the k^(th) channel are considered, that have a common or separate airsupply duct.

If the nominal value, if applicable, has a deviating value compared tothe actual value of an air pressure in the k^(th) air channel of am^(th) burner, the value can be modified by changing the cross-sectionof the k^(th) air channel. This, to be modified value for the airpressure of the k^(th) air within the k^(th) air channel for a m^(th)burner, respectively, is done by adjusting at least one air supplymodule within the k^(th) air channel, that can be built e.g. in form ofan air damper and can be changed and/or balanced.

In one version of the method it is envisaged, that the air pressure ofthe k^(th) air in the k^(th) air channel has an actual value P_(act) andthe cross-section of the k^(th) air channel a value A_(act). For thecross-section of the k^(th) air channel, for which the air pressureshould be modified, will be adjusted to a nominal value A_(nom.),whereby the air pressure of the k^(th) air in the k^(th) air channelwill be adjusted to a nominal value P_(nom). Consideration is given tothe relationship between the envisaged ratios of the pressure values,namely between the nominal value P_(nom) and the actual value P_(act.),and the square of the envisaged ratios of the cross-section values,namely the nominal value A_(nom.) and the actual value A_(act.), suchthat P_(nom.)/P_(act.) is proportional to (A_(act.)/A_(nom.))².According to this, the ratio of the nominal pressure value and theactual pressure value is inversely proportional to the square of theratio of the actual value and the nominal value of the cross-section. Asan alternative or additionally it can be considered, that the ratioP_(nom.)/P_(act.) is proportional to (V_(nom.)/V_(act.))². Thereby V isa volumetric flow rate of air through an air duct. According to this,V_(nom.) is a nominal value and V_(act.) an actual value for thevolumetric flow rate.

Due to the law of energy conservation respectively the Bernoulli law, inflow cross-section contractions, e.g. inside a pipe or air duct, thereis a quadratic correlation between the flow rate and the pressure dropacross that contraction, whereby P_(nom.)/P_(act.)˜(V_(nom.)/V_(act.))²applies. This correlation, on which many flow measurement device, e.g.orifice plates, venture nozzles etc. are based on, is used with theproposed method in order to derive the air flow rate by measuring theair pressure inside a burner.

On the air side, a burner can in this context be consideredsimplistically as an orifice plate, even though the burner does not havethe round cross-section of an orifice plate, but a cross-section ofpotentially rather complex geometry. The cross-section contractioninside a burner occurs in terms of fluid dynamics between the air supplymodule and the combustion chamber, there were the burner tile islocated. Whilst having the air supply module fully open normally approx.90% of the total air side pressure drop of a burner should be causedthere. One reason for this is, that than air has the maximum exitvelocity, for mixing the air and the fuel, which is also introduced inthis area to the furnace, most efficiently.

With the measurement of the static pressure at the already mentionedposition of the k^(th) air channel by inserting probes, the pressuredrop between the air pressure in the k^(th) air channel and ambientconditions can be measured. The pressure inside the k^(th) air channelcan also be measured against the pressure inside the firebox, which canbe measured by another probe located accordingly. As the burners areadjusted in comparison to the measured pressures and/or air flow rates,both alternatives are applicable.

In this embodiment, the air pressure of entire burner groups can bemeasured, where each burner group consists of one or more burners. Inthe same manner, the smallest cross-section in the vicinity of theburner tile should be chosen, whereby the cross-section of severalburners can be combined into a burner group.

With the adjustments of the air supply modules it is achieved, that theair flow in flow direction is changed in such way, that the pressuredrop through that part of the burner, that is just downstream of the airsupply module, is changed due to the changed air flow and measured bymeasuring the static air pressure.

For the correlation between the pressure and the cross-section appliesp_(nom.)/p_(act.)=f*(A_(act.)/A_(nom.))², whereby f is a factor ofproportionality. Provided that P_(nom.)=α*P_(act.), it applies that thecross-section is A_(nom.)=β*A_(act.), whereby α and β are factors ofproportionality. Here applies, according to above formulas, thatα=(f/β²). Accordingly the cross-section of the k^(th) air channel is tobe changed by the factor β=(f/α)^(0.5), if the air pressure of thek^(th) air is to be changed by the factor a.

In a possible embodiment of the method it is envisaged that for amultiple burner system the pressure for the k^(th) fraction of the airin the first k^(th) air channel of the first burner group or burner hasan actual value of P_(act.0)=p,0.

In the k^(th) air channel of a first next burner group or of a firstnext burner the pressure of the k^(th) air shows on the other hand anactual value P_(act. 1)<P_(act.0), that is by the factor α1 smaller,whereby α1*P_(act.)1=P_(nom.0)=P, ₀. In that case the cross-section ofthe k^(th) air channel in the first next burner group respectively thefirst next burner is to be enlarged from an actual value A_(act.1) by afactor β₁=(f/α1)^(0.5) to A_(nom.1)=(f/α₁)^(0.5)*A_(act.1). Furthermorethe pressure of the k^(th) air fraction in a second next burner grouprespectively in a second next burner shows an actual valueP_(act2)=α₂*P_(act0)=α₂* P_(nom.10), whereby this actual value P_(act.2)is by the factor a₂ larger than the foreseen nominal value P_(nom10). Inthat case the cross-section in the k^(th) air channel of the second nextburner group respectively the second next burner is to be reduced froman actual value A_(act2) by a factor β₂=(f/α₂)^(0.5) to the nominalvalue A_(nom2)=(f/α₂)^(0.5)*A_(act2).

However, it is also possible to use other measures to equalize the airpressure values of the k^(th) air in the k^(th) air channels of theburners.

The inventive setup shows at least one air pressure measurement devicein order to measure the air pressure values for the k^(th) air and ifapplicable control unit to compare, modify and balance eventuallydeviating values of the air pressure inside the k^(th) air channels. Asan alternative the adjustment of the air modules for the balancing ofthe air pressures can be done also manually.

At least one air measurement device is located centrally and designed tosimultaneously measure all air pressure values for the k^(th) air of allburner groups and/or burners.

The setup comprising besides at least one air supply module, that islocated inside the minimum one k^(th) air channel, also a number ofprobes respectively measuring probes, that are installed in order tomeasure air pressures in measuring locations, whereby along the k^(th)air channel of one burner group and/or one burner at least one of such aprobe is located, with which it is connected to at least one measuringdevice by means of e.g. an air hose.

The control unit is designed to modify the cross-section of a k^(th) airchannel by controlling an air supply module, which is located insidethis k^(th) air channel, typically by means of changing the openingposition of that air supply module.

For a multiple burner system of a furnace, comprising at least twoburners, the inventive method as well as the inventive setup allows theadjustment of an evenly distributed air flow by measuring the static airpressure in at least one location of the multiple burner system as wellas the collection of the measured static pressure values with the helpof the pressure measuring device in one location.

The measurement of the static pressure can be done as a pressure dropmeasurement between the measuring probe of the k^(th) air channel andambient or as an alternative between a measuring probe of the k^(th) airchannel and the combustion chamber of the furnace.

While applying the invention it is envisaged to collect the pressurevalues of the k^(th) air centrally in at least one location, while allk^(th) fractions of the supplied air of all burner groups and/or burnerare simultaneously captured respectively be transmitted allowing the airflow rates indirectly to be read off and/or compared to other burnergroups and/or burners of the multi burner system. Based on that, theadjustment of air dampers, whereby each burner group and/or each burnercomprising at least one air k^(th) air channel with one air damper, forall burner groups and/or burners, same air flow rates are assigned, aslong as the heat release is the same, whereby the effects of changingthe different air dampers opening positions can be centrally determined,compared and/or to be red off. If the heat release of individual burnersor burner groups are deviating from one another, the values for the airpressure of those burners respectively burner groups can be determinedby using the quadratic correlation between pressure drop andcross-section respectively the flow rate in the respective air channelin order to accomplish the correct air supply.

At least one burner of the multiple burner system, for which theinventive method is envisaged, can be designed as a so called diffusionburner. A diffusion burner mixes and finally ignites the fuel and air(combustion air) only in the area of the flame root. As an alternativeand additionally at least one burner can be designed as a premix or atleast partially premix burner, for which the combustion air is alreadymixed with the fuel, before it is physically reaching the flame root.

In industrial furnaces with a two burner or a multiple burner system thecombustion air is normally conveyed to the burners with the help of oneor more fans, exceptionally also with compressors, for example with apressure that is above 100 mbar, that inspires air from the environmentsending the air throughout a branched distribution system comprisingpipes and/or ducts to each individual burner. Thereby an air supply ductis normally connected with at least one, a k^(th) air channel,respectively. The air pressure in the distribution system is normallylow, for example less than 20 mbar. The low air pressure and thecircumstance, that the distribution system, due to his asymmetricgeometry of the air ducts and therefore different pressure drops andflow profiles, as well as due to eventually built in instruments, forexample a check valve and/or throttling devices, leads to unintentionaldeviating air flows to individual burners. For an ideal combustion thefuel-to-air ratio for each burners must have the same value, thereforethe distribution of air to all burners must be adjusted.

As the burners of a two burner or multiple burner system normally arefed with the same amount of fuel, that is to say the same heat release,all burners should receive the same amount of air and as a consequenceshould have the same fuel-to-air ratio. A gaseous or liquid fuel that isburned with air, is supplied normally with sufficient pressure, e.g. >1barg (for gases) and >4 barg (for liquids), so that all burners receivethe same amount of fuel and therefore the fuel is evenly distributed.

Normally burners are designed to let pass a certain air flow with thesame air damper opening position at the same air side pressure drop,that is to say if the flow rate to all burners is the same, than themeasured static pressure in all burners is the same.

In some cases the heat release to individual burners or burner groupscan be different from one to another. Customarily the air side pressuredrop of all burners is the same, that is to say at maximum heat releaseof a burner, independent from his size, the pressure drop is the same.If a first burner of a multiple burner system has an air side pressuredrop design of 10 mbar at a maximum heat release of 1 MW (Megawatt), asecond burner of the same multiple burner system with a max. heatrelease of 2.5 MW should have the same air side pressure drop of 10mbar. If this is the case, based on the measurement of the staticpressure of each k^(th) air of each burner the air flow rate of eachburner can be determined.

Using the method if the burners of the multiple burner system havedifferent air side pressure drop designs requires, that those pressurevalues are corrected with the quadratic correlation between flow rateand pressure drop. Thereby the flow rate is dependent of thecross-section of the k^(th) air channel. The same approach isapplicable, if burners of same construction but different heat releasesare operated.

A burner comprises at least one air channel, in which one or more airsupply modules for the adjustment and/or redistribution of air withinthe burner exists. Thereby the one or more air channel is connected withthe air supply duct and/or flows into it. Such an air supply module isbuilt inside the k^(th) air channel of a burner and intended to changethe cross-section of the air channel, through which the air flows to theburner, whereby it is normally opened more, whereby the air channel withthe air supply module among other things can become either fully open,partially open or fully closed. Such an air supply module is typicallydesigned in form of an air damper or depending of the burnerconstruction, e.g. as a within itself rotatable register.

A burner, that has several air channels, has at least one air supplymodule per air channel. A burner with one air channel respectively aprimary air channel has one air module, e.g. a first air module orprimary air module. A burner with two air channels and therefore aprimary and secondary air supply has two air modules, namely a primaryand a secondary air damper. If a burner has three air channels, namely aprimary, secondary and tertiary air channel, he comprises three airmodules or air dampers that are named primary, secondary and tertiaryair dampers.

Single measurements for pressures are done with this method on allburners simultaneously in order to know the air distribution for aspecific moment, as the operating status of a furnace can change oftenand rapidly. The proposed method offers the operating staff thepossibility to measure and let indicate directly on site, e.g. directlynear the furnace, the air distribution to the burners respectivelyburner groups. Either the control unit detects the uniform ornon-uniform air distribution and consequently makes the changes to theair supply modules accordingly, or the operating staff reads off the airdistribution visually and makes the manual changes on the air supplymodules. The practically instantaneous response of such changes allowsthe control unit or the operating staff, to adjust an even or uniformair distribution without big efforts very quickly.

Further advantages of the invention can be derived from the descriptionand the attached figures.

Naturally, the attributes mentioned in the preceding as well as thefollowing sections do not only exist in the combinations outlined, butalso apply to other combinations or the single entities, without fallingoutside the remit of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be represented with the help of the schematic figuresand will be consecutively described in more details referring to thefigures.

FIG. 1 shows schematically a setup of a burner with primary air supply(FIG. 1b ) and a setup of a burner with primary and secondary air supply(FIG. 1a ).

FIG. 2 shows schematically a first setup of a multiple burner system indifferent operating states while applying a first way of the inventivemethod.

FIG. 3 shows schematically a second setup of a multiple burner system indifferent operating states while applying a second way of the inventivemethod.

FIG. 4 shows schematically a third setup of a multiple burner systemwhile applying a third way of the inventive method.

FIG. 5 shows schematically a forth setup of a multiple burner system,comprising at least two multiple burner systems as per FIG. 4, whileapplying a forth way of the inventive method.

The figures will be described coherently and comprehensively, similarreferences refer to similar components.

DETAILED DESCRIPTION

FIG. 1a shows schematically a first setup of a burner 2 with one airsupply channel 8 and two air supply channels 4, 6, who's inlet openingsboth are connected to a common air duct 8. An exit area of the first airchannel 4 is surrounded coaxially by the exit area of the second airchannel 6. Thereby the exit area of the second air channel 6 issurrounded and/or bordered by a burner tile respectively a burner tilecasing 10. Both air channels 4, 6 flow into the combustion chamber 12 ofa furnace. In the first air channel 4 is located downstream of the inleta first air supply module in form of an air damper 14. In the second airchannel 6 is located, downstream of the inlet, a second air module 16,again in form of an air damper.

This first setup of burner 2 has a primary and secondary air supply.During the operation of that burner 2 air respectively combustion air,that is here as well as in the following figures be symbolized withhatched arrows, will be supplied from the air supply duct 8 to the twoair channels 4,6. In the first air channel 4 is located and/or isconveyed a first air, also named primary air and is in this figure, aswell as in the following figures, symbolized by tight hatching frombottom left to top right. In the second air channel 6 is located and/oris flowing a second air, also named secondary air and is in this figureas well as in the following figures symbolized with a second hatchingfrom top left to bottom right.

Besides on the outer casing of the first air channel 4 there is a firstprobe 18 respectively measuring probe for the static air pressure insidethe first air channel 4 and on the outer casing of the second airchannel 6 a second probe 20 respectively measuring probe in order tomeasure the static air pressure inside that second air channel. Theouter casings of both air channels 4, 6 border the burner casing 2 orare identical with the burner casing 2, respectively.

Similar setups of burners 22, 24, 26, 28, 30 with double air supplies,which has the same components like the first setup of burner 2, are puttogether as components of a multiple burner system 32, 34, like it isschematically shown in the following FIGS. 2 and 3.

A second setup of a burner 36, which is schematically shown in FIG. 1b ,shows only a single air supply with one first air channel 38, wheredownstream of the inlet a first air supply module 40, in form of an airdamper, is shown. Along the outer casing of the first air channel 38there is furthermore a probe 42 located in order to measure the staticair pressure in that air channel 38.

It is possible that in a multiple burner system 32 (FIG. 2), 34 (FIG.3), 44 (FIG. 4), 46 (FIG. 5), that due to different pressure drops, flowprofiles, instruments and so forth within an air distribution system,comprising air supply ducts 3,8,84 as well as air channels 4,6,38,80,82,leads to a situation where individual burner groups 72, 72 a, 72 band/or burners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76b, 78, 78 a, 78 b to some extend vary in the amount of air that isconveyed to those sections. The static pressure is measured with thehelp of probes 18, 20, 42, 79, that are located on the casings of theindividual burners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a,76 b, 78, 78 a, 78 b.

For the burners 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b, that arelocated inside a common air plenum of each burner group 72, 72 a, 72 bthe air pressure is measured by probes 79, although those measure thepressure of the plenum of each burner group 72, 72 a, 72 b. The staticpressure can be captured and/or measured inside the air channel 4, 6,38, 80, 82 but also in other places. Normally such a probe respectivelymeasuring probe 18, 20, 42, 79 can also be located elsewhere on the airchannel 4, 6, 38, 80, 82 provided that the equivalent static pressure isstill representative for the air, that flows inside the air channel 4,6, 38, 80, 82.

The method envisages, that a measured value, here a static pressure,determines for each burner 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b,76, 76 a, 76 b, 78, 78 a, 78 b indirectly a flow rate of combustion airthrough a burner 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76b, 78, 78 a, 78 b. If values for the pressure of individual burners 2,22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 bof a multiple burner system 32, 34, 44, 64 are deviating from oneanother, it is envisaged, that the air supply modules 14, 15, 16, 17,40, that is to say the air dampers and/or air registers of the burners2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78b are adjusted, respectively opened respectively closed and thereforemodified that long, until all burners 2, 22, 24, 26, 28, 30, 36, 74, 74a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b have the same static pressure.

Thereby it is envisaged, that the values of the first air pressure(primary air) inside first air channels 4, 80 of all burners 2, 22, 24,26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b of themultiple burner system 32, 34, 44, 46 are compared with one another. Theanalogous, values of the pressure of a second air (secondary air) insidesecond air channels 6, 82 of all burners 2, 22, 24, 26, 28, 30, 36, 74,74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b of the multiple burner system32,34,44,46 are compared with one another.

Commonly a multiple burner system 32, 34, 44, 46 comprises a number ofburners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78,78 a, 78 b, whereby each burner 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74b, 76, 76 a, 76 b, 78, 78 a, 78 b, has several air channels 4, 6, 38,80, 82, that e.g. are connected via an plenum with a burner group 72, 72a, 72 b and with air ducts 3, 8, 84, 98. As part of the method for eachair channel 4, 6, 38, 80, 8 of each burner 2, 22, 24, 26, 28, 30, 36,74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b the internal air pressureis measured.

Besides all air pressure values of all k^(th) air channels 4, 6, 38, 8082 of all burners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a,76 b, 78, 78 a, 78 b are compared with one another.

Since generally all burners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b,76, 76 a, 76 b, 78, 78 a, 78 b of a multiple burner system 32, 34, 44,46, on the basis of the heat release, are supposed to be supplied withthe same amount of air, it is envisaged in this embodiment of theinvention, although not mandatory, to collect the values of alllocations where the pressure of the k^(th) air channel 4, 6, 28, 80, 82of all burners 2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76b, 78, 78 a, 78 b is measured and pulled together in at least onelocation, that is to say in one or more locations, of the multipleburner system 32, 34, 44, 46.

With this measure the values of the static pressure of the k^(th) airchannels 4, 6, 38, 80, 82 are easily comparable with one another and thedistribution of individual values, that is to say uniform or non-uniformdistribution, easy to be captured and to derive values for the air flowrates through all k^(th) air channels 4, 6, 38, 80, 82. If staticpressure values and therefore flow rates differ from one another, thanthe values will be readjusted by changing the air supply module 14, 15,16, 17, 40 settings in the k^(th) air channels 4, 6, 38, 80, 82 in away, that they are adapted to the respective heat releases.

FIG. 2 shows schematically a first burner 22, a second burner 24 and ax^(th) burner 26 of a total of n burners 22, 24, 26 of a firstconfiguration of a multiple burner system 32, that similar to burner 2of figure la, has a first air channel 4, comprising a first air supplymodule 14 in form of an air damper and a second air channel 6,comprising a second air supply module 16 in form of an air damper.Furthermore this multiple burner system 32 comprises a primary air duct3 for all burners 22, 24, 26. This common air duct 3 splits up intosecondary air ducts 3, whereby each of these secondary air ducts 8 isconnected with both air channels 4, 6 of each burner 22, 24, 26. Air,which is flowing from the primary air duct 3 and/or the secondary airducts 8, splits into a first air channel 4 and a second air channel 6for the burners 22, 24, 26 into a second air (secondary air).

As part of the method first probes 18, which are located at the casingof the first air channel 4 of all burners 22, 24, 26 give values for thefirst static air pressure respectively primary air pressure inside ofthe first air channels 4. With the help of second probes 20, which arelocated at the casing of the second air channel 6 or all burners 22, 24,26 gives values for the second static pressure respectively secondaryair pressure inside of the second air channels 6. Assuming that theburners 22, 24, 26 in a variation of the multiple burner system 32 havemore air channels, the static air pressure for those air channels wouldneed to be also measured, that is to say in the case of third airchannels inside the burners 22, 24, 26, third static pressurerespectively tertiary air pressure inside the third air channel of allburners 22, 24, 26 needs to be measured.

The results of the simultaneously executed measurements of the airpressures in both air channels 4, 6 of all burners 22, 24, 26 arecaptured and displayed for all air channels 4, 6 of all burners 22, 24,26 by the air pressure measurement device 49 in a central locationand/or captured like shown in diagram 50 “Pressuremeasurement/gauge−primary (white) and secondary air (black)” andautomatically displayed. Along the ordinate of a diagram 50 there areshown and made readable values for the static air pressure,respectively. Displaying of the measurements with the help of thepressure measuring device 49 can be done as described, although it isalso conceivable to display the pure numerical value withoutvisualization along an ordinate. The central pressure measuring device49 is connected furthermore with a control unit 51 for control that isto say to drive and/or control functions of the components of themultiple burner system 32. If the air supply modules 14, 16 are notautomated, a control unit is not needed and the relevant air supplymodules 14, 16 are adjusted manually respectively by hand.

Furthermore FIG. 2a shows a first operating situation of the multipleburner system 32, where it is envisaged, that the cross-sections of allair channels 4, 6 of all burners 22, 24, 26 are opened to maximum,meaning 100% open. Therefore all adjustable air supply modules 4, 6,shown as air flaps, within air channels 4, 6 are positioned parallel tothe direction of flow and hence oriented such that they result inminimal flow resistance.

As diagram 50 shows, there are different values for the first air insidethe first air channels 4 of all burners 22, 24, 26 as well as for thesecond air pressure inside the second air channels 6 of all burners 22,24, 26. The individual values are shown in diagram 50 as white bars 52,54, 56 for the values of the first air pressure and as black bars 58,60, 62 with the values for the second air pressure.

In detail the value for the first air pressure of the first air channel4 of the first burner 22 shows 40 pressure units, normally expressed inmm water column (bar 52). The value of the first air pressure in thefirst air channel 4 of the second burner 24 is 42 pressure units (bar54). For the x^(th) burner 26 the value of the first air pressure in thefirst air channel 4 is 51 pressure units (bar 56). Therefore the firstair pressures for the first air channels 4 of all burners 22, 24, 26 ofthe multiple burner system 32 differs from one another and as aconsequence differs the air flow rate to the burners 22, 24, 26.

The same applies for the values of the second air pressures in thesecond air channels 6 of all burners 22, 24, 26. Thereby the value ofthe second air pressure in the second air channel 6 of the first burner22 is 36 pressure units (bar 58), the value of the second burner in thesecond air channel 6 of the second burner 24 is 45 pressure units (bar60) and the value of the second air pressure in the second air channel 6of the x^(th) burner 26 is 47 pressure units (bar 62).

Diagram 50 in FIG. 2a shows, that inside the first air channel 4 of thex^(th) burner 26 exists the highest actual value for the first airpressure among all actual values for the first air pressure 4 of allburners 22, 24 of the multiple burner system 32. Furthermore existsinside the second air channels 6 of the x^(th) burner 26 the highestactual value of the second air pressure among all captured values forthe second air pressure inside the second air channels 4 of all burner22, 24 of the multiple burner system 32. That means, that the air flowsupplied throughout the air supply ducts 3, 8 is higher in flow rateand/or in the fraction of first and second air in burner 26 compared toburner 24 and furthermore higher than the flow in the first burner 22.

As part of the described embodiment of this method differencesrespectively deviations between actual values for the k^(th) airpressure in the k^(th) air channel 4, 6 of burner 22, 24, 26 and aenvisaged nominal value for the k^(th) air pressure in the k^(th) airchannel 4, 6 will be determined and compared with the help of thecentrally located pressure measuring device 49.

In order to balance the value variation among the first air pressures,as well among the second air pressures, the embodiment of the methodenvisages, that air supply modules 4, 6 will be adjusted by the controlunit 51 respectively by manual adjustment in controlled manner bychanging the cross-section inside the air channels 4, 6. With thedescribed setup it is envisaged, that all values for the pressure of thefirst air fraction are controlled and/or adjusted to e.g. 50 pressureunits and all values for the pressure of the second air fraction to e.g.45 pressure units and therefore being equalized.

In the here described setup of the method the cross-section of the firstair channel 4 of the x^(t)h burner 26 is changed, by the use of the airsupply module 14, which is located inside the air channel, reducing theopening by 30% to 70% open position, either by means of the control unit51 or as an alternative manually. In case of the first air channel 4 ofthe second burner 24 the cross-section will be changed by opening theair supply module 14 to 80%, whereby the cross-section is reduced by20%. As a result the actual value of the pressure of the first air willraise from 40 pressure units to the nominal value of 50 pressure units,as normally the total air flow to all burners 22, 24, 26 is keptconstant by means of e.g. a control unit of the furnace and/or theburners 26.

For the second air inlet 6 in the x^(th) burner 26 it is envisaged, thatthe cross-section is changed by the second air supply module 16, whichis controlled by the control unit 51 or manually, by decreasing theopening by 40% to 60% open position. Furthermore will the cross-sectionof the second air inlet 6 of the second burner 24 be adjusted bycontrolled adjustment of the second air supply module 16 with help ofthe control unit 51 or manually reducing the opening by 10% to 90% openposition. As a result the actual value for the pressure of the secondair fraction of the first burner will increase from 36 pressure units to45 pressure units.

While adjusting the air supply modules 4, 6 in the k^(th) air channel 4,6 of a burner 22, 24, 26 at first it will be determined the differenceof an actual and a nominal value in the k^(th) channel 4, 6 and the airpressures of the respective burner 22, 24, 26 and from there derived byhow much percent a cross-section of the respective k^(th) air channel 4,6 of the respective burner 22, 24, 26 must be reduced or enlarged. Assoon as it is determined, by how much percent the cross-section of theair channels 4, 6 of a burner 14, 16 is to be reduced, the finalcross-section will be adjusted considering the geometry of the airsupply modules 14, 16 located inside the air channels 4, 6 by turningthe air damper.

In order to balance the values for the air pressures it is not decisivewhich one has the maximum value. The method envisages, that a burner canbe operated on a higher heat release and therefore requires more air. Inthis case higher air pressures are required compared to those burnersthat operate on lower heat release. It can be also required, to favorthe first compared to the second air and in certain circumstances thefirst air pressure is higher than the second air. If all burners 22, 24,26 are of identical construction and all fire the same heat release,meaning the air flow rate to all burners 22,24,26 should be the same andif the values of table 64 are applicable, then the second burner 24 andabove all the x^(th) burner 26 must be adjusted. By throttling the airdampers of the x^(th) burner 26 air is shifted more towards the otherburners 22, 24. Thereby it is considered, that the total air flow, thatcomes from a fan, is normally kept constant by means of an automatedcontrol loop in the DCS (Distributed Control System) of a multipleburner system 32, whereby a non-uniform air distribution to all burners22, 24, 26 is eliminated.

As part of the method by comparing the pressures, it can be checked, atwhich burner 22, 24, 26 which air damper needs to be adjusted. Therebyit is not required, to know the absolute total air flow to each burners22, 24, 26. Instead all relative differences between burner specific airflows, that is to say primary, secondary and tertiary air are comparedwith one another and in case of deviations be adjusted and/or equalized.

As a result follows a second operating situation for the burners 22, 24,26 of a multiple burner system 32 that is shown schematically in FIG. 2b. Table 64, which is displayed with the help of the control unit 51,shows among other things, by how much percent the cross-section of theair channels 4, 6 of the individual burners 22, 24, 26 is to be openedor as an alternative if the air dampers are adjusted manually it can bedetermined by reading off the physical positions on the dampers. The bar152, 154, 156, 158, 160, 162 in diagram 150 shows, that in the first airchannel 4 of all burners 22, 24, 26 now the same air pressure with avalue of 50 pressure units exists. The values of the second air pressurein the second air channel 6 of the burners is 45 pressure units.

Based on FIG. 2c a method is described, for with which the air supply toa multiple burner system 32 can be optimized, if the heat release to theburners 22, 24, 26 is different from one another. It is assumed, thatthe heat release of the first and second burner 22, 24 is 1 power unit(e.g. Megawatt)—see table 264. The heat release of the x^(th) burner 26is 20% higher meaning 1.2 power units. As a consequence the air flowrequired for the x^(th) burner 26 must be 20% higher compared to theother burners 22, 24. By how much the respective pressure of therespective air must be higher, derives from the quadratic correlationbetween pressure drop Δp_(k), that is to say the pressure drop Δp₁ ofthe first air and the pressure drop Δp₂ of the second air, as well asthe cross-section A_(i) for the respective k^(th) air fraction,according the proportionality ratio Δp₁=Δp₂˜(proportional) (A₂/A₁)²respectively Δp₁=Δp₂˜(ΔV₁/ΔV₂)², whereby ΔV_(i) is a respective flowrate.

For the x^(th) burner 26 this means, that the pressure of the k^(th) airmust be adjusted by the factor (1.2/1)², that is to say 44% higher thanthe other burners 22, 24. This can be accomplished by opening/closing ofa respective air supply module 14, 16. In that way it is possible, touse the pressure measurement device 49 not only in order to balance theair supply to the burners 22, 24, 26 when operating at same heatreleases, but also when the burners 22, 24, 26 are operating ondifferent heat releases, so that finally the mixture of fuel and air isadjusted to every burner 22, 24, 26 adequately.

Considered here is also that the combustion chamber internal pressure,which is connected with the burner 22, 24, 26 and a pressure of ambientair, whereby the pressure inside the combustion chamber is normallynegative. Considering additionally the pressure values inside thecombustion chamber, as well as the ambient air and the pressure in theair channels 4, 6 the values for the air pressures of the first andsecond air of the first and second burner 22, 24 will be balanced,compare to bar 252, 254, 256, 258, 260, 262 in diagram 250. Thereforethe air pressure of the first air in the first air channel 4 of thefirst burner 22 (bar 252) matches the air pressure of the first air inthe first air channel 4 of the second burner 24 (bar 254) and the airpressure of the second air in the second air channel 6 of the firstburner 22 (bar 258) matches the air pressure of the second air in thesecond air channel 6 of the second burner 24 (bar 260).

FIG. 3 shows schematically a second setup of a multiple burner system 34with two burners 28, 30 that each has two air channels 4, 6 and similarto previous burners 12, 22, 24, 26 as per FIGS. 1a, 2a and 2b areconnected with one air supply duct 8. FIG. 3 shows furthermore ameasuring setup 70 for the control of the operation of a multiple burnersystem 34, as well as at least one step of the embodiment of thismethod. Besides also here each combustion chamber has a proberespectively measuring probe 13 in order to measure the pressure.

As shown schematically in FIG. 3a , one first probe 18 is connected onthe casing of a first air channel 4 of the first burner 28 via a firstconnection, e.g. in form of an air hose, to a first leg of a first “U”type pressure measuring device 66. A first probe 18, attached on thecasing of a first air channel 4 of the second burner 30, is connectedvia a second connection, e.g. in form of an air hose, to a second leg ofa first “U” type pressure measuring device 66. The level of the “U” typepressure gauge liquid shows, that the first air pressure in the firstchannel 4 of the first burner 28 has a higher pressure than the firstair pressure in the first air channel 4 of the second burner 30.

A second probe 20 attached on the casing of a second air channel 6 ofthe first burner 28 is connected via a third connection, e.g. in form ofan air hose, to a first leg of a second “U” type pressure measuringdevice 68. A second probe 20 attached on the casing of a first airchannel 6 of the second burner 30 is connected via forth connection,e.g. in form of an air hose, to a second leg of a “U” type pressuremeasuring device 68. The level of the liquid of the “U” type pressuremeasuring device shows here, that the second air pressure in the secondair channel 6 of the first burner 28 is higher than the second airpressure in the second air channel 6 of the second burner 30.

In this setup cross-sections of the air channels 4,6 of the first burner28 will be reduced by adjusting the internal air supply modules 14, 16and therefore reduces the values for the existing air pressures, untilinside the first air channels 4 of both burners 28, 30 the same firstair pressure and in the second air channel 6 of both burner 28, 30 thesame air pressure is achieved, which finally leads to same liquid levelin the “U” type pressure measuring devices 66, 68—as indicated in FIG. 3b.

In this shown setup with only two burners 28, 30 of same air sidepressure drop design, the probes 18, 20 for the measurement of the airpressures are connected to one leg of the “U” type pressure gauge.However any other pressure measuring device 66, 68 can be used tocapture and/or compare the pressure values. With the here presentedsetup it is possible to equalize and/or even out the pressure values ofa non-uniform distribution of air in both, the first air channels 4 aswell as in the second air channels 6, of both burners 28,30 of amultiple burner system 34.

A forth setup of a multiple burner system 44 is shown schematically inFIG. 4 comprising a burner group 72 with a distribution chamber, whichis also called a “plenum”. If a multiple burner system comprises of moreplena, one burner group 72 is arranged within a respective plenum.

FIG. 5 shows two such burner groups 72 a, 72 b with plena, whichconstitute another configuration of a multiple burner system 46. Howeverit could be any number of burner groups 72, 72 b.

Every burner group 72, 72 a, 72 b consists of several burners 74, 74 a,74 b, 76, 76 a, 76 b, 78, 78 a, 78 b of which in FIGS. 4 and 5 are showna first burner 74, 74 a, 74 b, a second burner 76, 76 a, 76 b and ay^(th) burner 78, 78 a, 78 b. Each of these burners 74, 74 a, 74 b, 76,76 a, 76 b, 78, 78 a, 78 b comprises one first internal air channel 80and a second internal air channel 82. Thereby via every first internalair channel 80 a first air respectively primary air is supplied to acombustion chamber 12 of a furnace, whereas via every second internalair channel 82 a second air respectively secondary air is supplied tothe combustion chamber 12.

At the casing of the plenum of a burner group 72, 72 a, 72 b there isarranged at least one air duct 3, by which air is supplied to the plenumin which the burner group 72, 72 a, 72 b is located.

At least one air duct 3 is coupled to an air duct 84 that sits acrossthe burner and/or within a distribution plenum. The air channels 80, 82inside the burner are thereby coupled to the superordinate air duct 84that sits across the burner and/or within a (distribution) plenum and isgenerally identical with the (distribution) plenum itself.

Therefore air flows from at least one air supply duct 3 into an air duct84 that sits across the burner and/or within a distribution plenum. Thisair splits up for each burner 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a,78 b separately throughout the burner internal air channels 80, 82 intofractions, namely a first air inside the respective first air channel 80as well as a second air inside the respective second air channel 82.

The air, which is supplied from at least one air duct 3 and/or theplenum internal air duct 84, will be distributed freely within eachplenum comprising the burner groups 72, 72 a, 72 b. The internal spaceof the plena 72, 72 a, 72 b of the burner groups 72, 72 a, 72 b, whichis formed by the superordinate air duct 84 and the burners 74, 74 a, 74b, 76, 76 a, 76 b, 78, 78 a, 78 b provides air supply to all burners 74,74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b. When air is arriving at theburners 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b, the air will berouted through the air channels 80, 82 by opening and/or closing of theair supply modules 15, 17.

It is envisaged, that along the burner enclosing and/or internal plenuminternal air duct 84 respectively on the plenum of burner group 72, 72a, 72 b at least one measuring probe 79 is arranged, with which the airpressure is measured. As in this method merely the air pressure valuesinside the plenum of a burner group 72, 72 a, 72 b are measured, onlythe air flow of an entire plenum of one burner group 72, 72, 72 b iscomparable to another plenum of another burner group 72, 72 a, 72 b.This approach can be helpful because in this setup respectively way ofconstruction of air supply modules 15, 17 the measurement of airpressure inside the air channels 80, 82 can be difficult.

The in FIG. 5 schematically shown setup of a multiple burner system 46comprising x burner groups 72 a, 72 b as presented already in FIG. 4,whereby here only one first burner group 72 a (plenum 1) and a x^(th)burner group 72 b (plenum x) is shown. Each of those burner groups 72 a,72 b comprising here one plenum with a total of y burners 74 a, 74 b, 76a, 76 b, 78 a, 78 b with a first and a second internal air channel 80,82 each. Analogous to the multiple burner system 44 shown in FIG. 4, theair is supplied via the burner enclosing and/or plenum internal air duct84 by distributing freely towards the y burners 74 a, 74 b, 76 a, 76 b,78 a, 78 b.

During the operation of the multiple burner system 46 the combustion airis supplied from a reservoir and/or a fan 96 via an air duct system 98,in which valve and/or dampers respectively air supply modules 100 arearranged, guiding the air to several air ducts 3 and finally leading tothe burner groups 72 a, 72 b. The supplied air is split up inside of theplena of the burner groups 72 a, 72 b.

Along at least one air duct 3 of the first burner group 72 a arearranged at least one, here several measuring probes 79 in differentlocations, that are connected with a first intersection 102 for allmeasuring probes 79. At this first intersection point 102 the airpressure inside the plenum 74 a is measured. The value for the airpressure is determined and if applicable directly displayed by a centrallocated pressure measuring device 104 in form of a diagram 106 andvisible as a first white bar. Similarly, there are several measuringprobes 79 at different measuring points along one air duct 3 of thex^(th) burner group 72 b, that connect all measuring probes 79 with thex^(th) intersection 108. At this x^(th) intersection 108 the airpressure for the x^(th) burner group 72 b and therefore for that plenumis measured. An air pressure value for burner 74 b, 76 b, 78 b of thex^(th) burner group 72 b is also captured by the central pressuremeasuring device 104 and displayed in diagram 106 by means of a second,black bar. The central pressure measuring device 104 acts together witha control unit 110 for the control of the multiple burner system 46applying the method. As an alternative the multiple burner system 46 canalso be operated manually that is to say without a control unit 110.

To modify the measured air pressure or air flow values, respectively,the cross-sections of the air ducts are changed by adjusting the airsupply modules 100 considering the proportionalityP_(nom.)/P_(act.)˜(A_(act.)/A_(nom.))² orP_(nom.)/P_(act.)˜(V_(nom.)/V_(act.))², respectively. In thisconfiguration, the total air flow for each plenum are compared with oneanother. Normally there are no separate plena for the first or secondair. Each plenum supplies the first and second air in the same manner.Air flows for the individual burners 74, 74 a, 74 b, 76, 76 a, 76 b, 78,78 a, 78 b or the k^(th) air channel are thus no longer distinguishable.A position of the k^(th) air supply module 15 is hence the same for allburners 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b of the sameplenum. This also applies for the k^(th) air supply modules 17, wherebythe position of all air supply modules 15 can be different to those ofair supply modules 17, e.g. the air supply modules 15 can be opened 30%and air supply modules 17 100%.

As diagram 106 shows, the air pressure value in the first burner group72 a is lower than in the x^(th) burner group 72 b. If all burners 74 a,74 b, 76 a, 76 b, 78 a, 78 b of all burner groups 72 a, 72 b areoperated with the same heat release, hence requiring the same airquantities, the x different air pressure values are equalized bycontrolled adjustment of at least one air supply module 100. This moduleis arranged along the at least one air supply duct 3, that leads to thefirst burner group 72 a and increases the air while opening the airsupply module 100 until both plenum specific values are the same. As analternative the air supply module 108 of the second burner group 72 bcan be closed more.

If different heat releases are run in burner groups 72 a, 72 b, then theair pressure needs to be adjusted according to the quadraticrelationship between pressure, and pressure drop respectively, and thecross-section of the air channels 80, 82 as already described in FIG. 2.

The concept as described in FIGS. 2 and 3 is basically also usable forgroups of burners 74, 74 a, 76, 76 a, 78, 78 a within burner groups 72,72 a, 72 b, if individual measurements at each burner 74, 74 a, 76, 76a, 78, 78 a are possible.

Furthermore, the described method to measure the air distribution canalso be used for furnaces with natural draft burners without airducting. In that case, pressure values of a combustion chamber 12 willbe measured via parallel measurements with several measuring probes 13of the combustion chamber 12, by comparing the direct simultaneousreadings.

1. Method for operation of a multiple burner system (32, 34, 44, 46),comprising two or more burner groups (72, 72 a, 72 b), wherein eachburner group (72, 72 a, 72 b) is associated with at least one air intakeduct (3, 8, 84, 98) through which air is supplied to the burner group(72, 72 a, 72 b), wherein each burner group (72, 72 a, 72 b) has atleast one k^(th) air channel (4, 6, 38, 80, 82) with which the suppliedair is divided up into an k^(th) air, wherein for each k^(th) airchannel (4, 6, 38, 80, 82) of all burner groups (72, 72 a, 72 b) an airpressure value is measured for the k^(th) air for all burner groups (72,72 a, 72 b), wherein all air pressure values measured for k^(th) air forthe burner groups (72, 72 a, 72 b) are compared with one another, todetermine whether the air pressure values for the k^(th) air for theburner groups deviate from one another, wherein deviating arc pressuresfor the k^(th) air are changed inside the k^(th) air channel (4, 6, 38,80, 82).
 2. The method as in claim 1, in which all measured air pressurevalues for the k^(th) air are collected at one location and comparedwith one another.
 3. The method as in claim 1, performed for a multipleburner system (32, 34, 44, 46) with a number of burner groups (72, 72 a,72 b), wherein each burner group (72, 72 a, 72 b) comprises at least oneburner (2, 22, 24, 26, 28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78,78 a, 78 b), wherein each burner (2, 22, 24, 26, 28, 30, 36, 74, 74 a,74 b, 76, 76 a, 76 b, 78, 78 a, 78 b) is associated with at least oneair supply duct (3, 8, 84, 98), through which the burner (2, 22, 24, 26,28, 30, 36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78 b) is suppliedwith air, wherein each burner (2, 22, 24, 26, 28, 30,36, 74, 74 a, 74 b,76, 76 a, 76 b, 78, 78 a, 78 b) has the k^(th) air channel (4, 6, 38,80, 82), with which the air supplied is divided up into the k^(th) air,wherein for each k^(th) air channel (4, 6, 38, 80, 82) for all burners(2, 22, 24, 26, 28, 30,36, 74, 74 a, 74 b, 76, 76 a, 76 b, 78, 78 a, 78b) the air pressure value for the k^(th) air is measured, wherein allair pressure values measured for the k^(th) air are compared with oneanother to determine whether the air pressure values for the k^(th) airfor the burners (2, 22, 24, 26, 28, 30,36, 74, 74 a, 74 b, 76, 76 a, 76b, 78, 78 a, 78 b) deviate from one another, wherein deviating airpressure values for the k^(th) air are changed within the k^(th) airchannel (4, 6, 38, 80, 82).
 4. The method as in claim 1, in which an airpressure value for the k^(th) air channel (4, 6, 38, 80, 82) is changedby changing the cross-section of the k^(th) air channel (4, 6, 38, 80,82).
 5. The method as in claim 1, in which an air pressure value for thek^(th) air channel (4, 6, 38, 80, 82) is changed by changing at leastone air supply module (14, 15, 16, 17, 40, 100) located inside thek^(th) air channel (4, 6, 38, 80, 82).
 6. The method as in claim 5, inwhich the air pressure value for the k^(th) air is changed inside thek^(th) air channel (4, 6, 38, 80, 82) with at least one air supplymodule (14, 15, 16, 17, 40, 100) designed as an air damper.
 7. Themethod as in claim 4, in which the air pressure of the k^(th) air in thek^(th) air channel (4, 6, 38, 80, 82, 84) has an actual value ofp_(act.) and the cross-section of the k^(th) air channel (4, 6, 38, 80,82, 84) has an actual value of A_(act.), wherein for the cross-sectionof the k^(th) air channel (4, 6, 38, 80, 82, 84) a nominal value ofAnom. is set, wherein for the air pressure of the k^(th) air in thek^(th) air channel (4, 6, 38, 80, 82, 84) a nominal value of p_(nom.) isset, wherein P_(nom.)/P_(act.) is proportional to (A_(act.)/A_(nom.))².8. Setup for operation of a multiple burner system (32, 34, 44, 46),comprising two or more burner groups (72, 72 a, 72 b), wherein eachburner group (72, 72 a, 72 b) is associated with at least one air intakeduct (3, 8, 84, 98), through which air is supplied to the burner group(72, 72 a, 72 b), wherein each burner group (72, 72 a, 72 b) has atleast one k^(th) air channel (4, 6, 38, 80, 82), with which the suppliedair is divided up into an k^(th) air, wherein the setup includes atleast one pressure measuring device (49, 66, 68, 104) designed formeasuring an air pressure value for the k^(th) air for each k^(th) airchannel of all burner groups (72, 72 a, 72 b) wherein all air pressurevalues measured for k^(th) air for the burner assemblies (72, 72 a, 72b) are to be compared with one another, to determine whether the airpressure values for the k^(th) air for the burner groups (72, 72 a, 72b) deviate from one another, wherein deviating air pressures for thek^(th) air are to be changed inside the k^(th) air channel (4, 6, 38,80, 82, 84).
 9. The setup as in claim 8, in which at least one pressuremeasuring device (49, 66, 68, 104) is located centrally and designed tosimultaneously measure all air pressure values for the k^(th) air. 10.The setup as in claim 8, comprising a number of probes (18, 20, 42, 79)for measuring the air pressure, wherein along the k^(th) air channel (4,6, 38, 80, 82, 84) at least one probe (18, 20, 42, 79) is located, whichis connected to at least one pressure measuring device(49, 66, 68, 104).11. The setup as in claim 8, comprising at least one air supplymodule(14, 15, 16, 17, 40, 100) located inside the k^(th) air channel(4, 6, 38, 80, 82, 84), designed to change a cross-section of the k^(th)air channel (4, 6, 38, 80, 82, 84).
 12. -The setup as in claim 8,comprising a control unit (51, 110) designed to compare all air pressurevalues measured for the k^(th) air of all burner groups (72, 72 a, 72 b)with one another and to determine whether the air pressure values forthe k^(th) air of all burner groups (72, 72 a, 72 b) deviate from oneanother, wherein the control unit (51, 110) is designed to change thecross-section of the k^(th) air channel (4, 6, 38, 80, 82, 84) andcompensate any deviating air pressure value for the k^(th) air withinthe k^(th) air channel (4, 6, 38, 80, 82, 84).